Wheeled carts that connect to each other to form a train of carts towed by a tugger are commonly used to transport materials in a warehouse. Each cart has a chassis supported on wheels, a hitch at the rear end of the chassis, and a drawbar at the front end of the chassis. The distal end of the drawbar of each chassis is configured to be coupled to the hitch of an adjacent cart as well as the hitch of a tugger.
An existing configuration for the drawbar and hitch coupling involves a hitch that includes a rearward extending plate with a vertically oriented aperture (“hitch hole”). The drawbar terminates with a downwardly extending boss (“the boss”) configured to be received in the aperture of a hitch hole. Typically, the drawbar is configured to pivot at least about a horizontal axis, which allows the boss of one cart to be conveniently connected to the hitch hole of another cart by simply pivoting counter clockwise (upward) the drawbar, aligning the boss with the hitch hole, and dropping the drawbar thereby engaging the boss of the drawbar with the hitch hole. The hitch hole of the cart and tugger may or may not be at the same height from the ground. The connection between the boss and the hitch hole allows the boss to pivot relative to the hitch hole about a vertical axis thereby allowing the carts to track in when pulled.
The existing configuration is desirable at least in part because it is simple. There are very few moving parts to maintain and the connection is fast and efficient. However, a disadvantage of the current system is that the carts can inadvertently disconnect from another cart or the tugger if the drawbar pivots counterclockwise, which can happen if the carts travel over a bump or if they are stopped abruptly. The present disclosure provides a system and method that preserves the advantages of the existing system while also addressing the drawbacks of the existing system.